Re: [PATCH] Hexagon (target/hexagon) make VyV operands use a unique temp

[Philippe Mathieu-Daudé]

On 7/6/22 00:23, Taylor Simpson wrote:
> VyV operand is only used in the vshuff and vdeal instructions.  These
> instructions write to both VyV and VxV operands.  In the case where
> both operands are the same register, we need a separate location for
> VyV.  We use the existing vtmp field in CPUHexagonState.
>
> Test case added in tests/tcg/hexagon/hvx_misc.c
>
> Signed-off-by: Taylor Simpson <tsimpson@quicinc.com>
> ---
>   tests/tcg/hexagon/hvx_misc.c    | 45 +++++++++++++++++++++++++++++++++
>   target/hexagon/gen_tcg_funcs.py |  9 +++----
>   2 files changed, 49 insertions(+), 5 deletions(-)

> +static void test_vshuff(void)
> +{
> +    /* Test that vshuff works when the two operands are the same register */
> +    const uint32_t splat = 0x089be55c;
> +    const uint32_t shuff = 0x454fa926;
> +    MMVector v0, v1;
> +
> +    memset(expect, 0x12, sizeof(MMVector));
> +    memset(output, 0x34, sizeof(MMVector));
> +
> +    asm volatile("v25 = vsplat(%0)\n\t"
> +                 "vshuff(v25, v25, %1)\n\t"
> +                 "vmem(%2 + #0) = v25\n\t"
> +                 : /* no outputs */
> +                 : "r"(splat), "r"(shuff), "r"(output)
> +                 : "v25", "memory");
> +
> +    /*
> +     * The semantics of Hexagon are the operands are pass-by-value, so create
> +     * two copies of the vsplat result.
> +     */
> +    for (int i = 0; i < MAX_VEC_SIZE_BYTES / 4; i++) {

Nitpicking, possibly 4 -> sizeof(v0.uw[0]).

> +        v0.uw[i] = splat;
> +        v1.uw[i] = splat;
> +    }

Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>